Valve for air-compressors.



No. 632,490. Patented Sept. 5, I899.

JJHEMPHILL.

VALVEv FOR AIR COMPRESSORS,

(Application filed July 11, 1898.)

(No Model.)

WITNESSES;

Yg-u: NORRIS PUERS FHOTO-LITHO., wAsHmcmN, D. c.

UNITED STATES PATENT OFFICE.

JAMES I-IEMPIIILL, OF PITTSBURG, PENNSYLVANIA.

VALVE FOR AIR-COMPRESSO RS.

SPECIFICATION forming part of Letters Patent No. 632,490, datedSeptember 5, 1899.

Application filed July 11, 1898. Serial No. 685,579. (No model.)

To aZZ whom it may concern.-

Be it known that I, JAMEs HEMPHILL, a citizen of the United States,residing at Pittsburg, in the county of Allegheny'and State ofPennsylvania, have invented or discovered certain new and usefulImprovements in Valves for Air-( ompressors, of which improvements thefollowing is a specification.

The invention described herein relates to certain improvements in valvesfor blowingengines, and has for its object a construction whereby themovements of the valve may be controlled or regulated so as to preventthe excessive hammering incident to the valves now in use.

In general terms the invention consists in the construction andcombination substan; tially as hereinafter more fully described andclaimed.

In the accompanying drawing, forming a part of this specification, isshown a sectional elevation of my improved valve.

In the practice of my invention an open grid or guide frame 1 isarranged transversely heads 2 and 3,'and a shoulder 4 on its inner endis held against a seat'formed around the opening through the head 2 byset-screws 5,

passing through the cap-plate 6 and bearing against the outer end of thegrid or guide The cap-plate 6 is bolted over the:

frame. opening through the outer head 3 and is provided with a hollowboss or sleeve '7, which serves as a guide for the stem 8 of the valve9, secured to the inner end of the stem. The valve is yieldingly held tothe seat, formed by an inwardly-projecting shoulder 10 on the grid orguide frame 1, by a spring 11, which bears at one end against the valveand has its opposite end seated in a socket 12,'formed on the end of theboss 7.

In order to prevent the hammering of the valve due to its sudden openingby the airpressure in the cylinder and to the closing action of thespring when pressures in the cylinder and air-chamber are equalized,thevalve is connected to a cushioning mechanism which is constructed ashereinafter described. The outer end of the valve-stem 8 is secured to apiston 13, arranged to operate within a cylinder 14. This cylinder isformed on or connected to the cap-plate 6. This cylinder is providedwithin its walls with openings 15 for the escape of air as the piston isshifted by the valve 9 in its opening movement, and the holes are solocated with reference to the traverse of the piston as to be closed bythe piston just before the valve has reached the desired limit of itsopening movement. The further movement of the piston will be re sistedby the air confined between the piston and the end of the cylinder. Theair thus confined is prevented from acting to force the valvetoward itsseat before the pressures in the blowing-cylinder and air-chamber areequalized by permitting aregulated escape of 'the air-cushion through apetcock 16 or other suitable regulating device. By suitably adj ustingthe petcock the movement of the piston 13 will be gradually checked andthere will not be any material pressure against the piston when stoppedtending to close the valve. It will be readily understood that the portsor openings 15 will permit the desired quick opening of the valve.

The movement of the valve as it approaches its seat under the action ofthe spring 11 is checked and regulated by means of one or more petcocksor valves 17, which are properly adjusted to control the escape of air,forming a cushion between the piston 13 and the inner end of thecylinder 14 during the closing movement'of the valve.

It is characteristic of my improvement that the valve is held closed byits spring until a predetermined pressure has been produced in thecylinder and that as soon as such pressure is reached the valve will beautomatically shifted, and as soon as pressures in the cylinder andair-receiver are equalized the valve will be quickly closed by thespring. It is further characteristic of my improvement that although'theopening and closing movements of the valve are quick and full allhammering or jarring is prevented without any material interference withsuch prompt movements.

I claim herein as my invention- The combination of a valve, a spring forholding the valve on its seat during the normal operation of thecompressor, a cylinder having its piston connected to the valve said Intestimony whereof I have hereunto set cylinder being provided with oneor more my hand. ports permitting the free escape of air during aportion of the movement of the piston 5 and with a valved port for theregulated es- Witnesses:

cape of air during the final movement of the F. E. GAITHER, piston,substantially as set forth. DARWIN S. WOLCOTT.

JAMES HEMPHILL.

